Opponents of big bang cosmology, both atheists and young-earth creationists, frequently attempt to push aside very compelling and overwhelming physical evidence for this biblically predicted model by picking apart the limitations on astronomers' ability to attain accurate and reliable measurements of distances to galaxies.1
All cosmic distance measures are ultimately based on plane geometry theorems. For example, if one knows the length of the base of an isosceles triangle, then measurements of the angles at either end of the base will deliver the distance to the vertex of the triangle. This is known as the direct distance method. The diameter of Earth's orbit about the Sun (about 185,912,076 miles or 299,195,741 kilometers) has traditionally been the base of the triangle used to determine distances to nearby stars. But this base is so tiny (astronomically speaking) that distances to even the nearest stars can be ascertained to an accuracy of no better than a few percent.
Herein lies the rub. In order to gain any gage of the universe's history, and insights into its creation event, astronomers must use their limited direct distance measures to calibrate indirect distance methods for more distant objects. The indirect methods, though internally more accurate than the direct methods, make certain assumptions about the properties of the observed objects. However, the various indirect methods each make distinctly different assumptions.
There are two ways astronomers can make their distance measurements to galaxies more secure. One, they can push their accurate direct distance determinations out to much greater distances, hopefully to galaxies themselves. Two, they can assemble a number of accurate but different indirect distance measurements. If these various indirect methods yield consistent results they will establish that the different inherent assumptions about the studied objects are well understood and accounted for. If the indirect methods are also consistent with a direct method at a comparable distance then astronomers can be certain that they really do have accurate and reliable knowledge of the distances to galaxies. Therefore, they can be very confident about the (biblically predicted) big bang model.
Three American astronomers recently completed such a comparison of distance measuring methods to the galaxy NGC 4258.2 NGC 4258 is unique in that several water masers revolve around the supermassive black hole at its center. The positions and orbits of these masers can be determined to an extremely high degree using electronically linked radio telescopes all over the world to create an instrument with an angular resolving power a hundred times superior to that of the Hubble Space Telescope. The spectra of the maser sources yielded the orbital velocities of the sources about the black hole. Newton's laws of motion translated those velocities into measured diameters for the orbits. With accurate calculations of the angles subtended by the orbits combined with precise measurements of the diameters of the orbits in kilometers, the team used plane geometry theorems to calculate a direct distance to NGC 4258. The result was 23.41 ± 0.97 million light-years.
Another special feature of NGC 4258 is that it is a large, relatively nearby spiral galaxy that contains many well-measured Cepheid variable stars within its disk (see here and here) and many well-measured stars at the tip of the red giant branch within its halo (see here and [here]http://en.wikipedia.org/wiki/Asymptoticgiantbranch)). Thus, NGC 4258 allows astronomers to accurately measure its distance using the two best indirect methods, one based on Cepheid variable stars and the other based on stars at the tip of the red giant branch.
In 2001, the three astronomers, as part of the Hubble Space Telescope Key Project, determined a distance to NGC 4258 based on Cepheid variable stars.3 In their current study they apply a set of reddening and metallicity corrections to the Key Project results to develop an improved distance measurement. The new calculation for NGC 4258 was 23.41 ± 0.22 million light-years.
Most of the scientists' research paper is devoted to their measurement of the distance to NGC 4258 based on halo stars at the tip of the red giant branch. In this case the distance they determined for NGC 4258 came to 23.41 ± 0.43 million light-years.
For the three distance-measuring methods the quoted error bars only consider possible random errors. They do not take into account errors that could have been generated by possibly misunderstood or miscalculated assumptions. However, the fact that the three separate methods yield identical results strongly implies that astronomers have properly interpreted and taken into correct account the underlying assumptions.
This stunning confirmation of the reliability of astronomers' distance measurements to galaxies means that we can now enjoy a much more secure picture of the universe's expansion history, of the cosmic creation event, and of the time back to the cosmic creation event. These new measurements on NGC 4258 remove any reasonable doubt that we live in a purposefully designed universe that was created many billions of years ago. Further confirmation will come in a year or two when this same team of astronomers publishes a new direct distance measurement that they promise will be three times more accurate (see here and here).4
- Hugh Ross, The Creator and the Cosmos 3rd ed. (Colorado Springs, NavPress, 2001), 23-29.
- Violet A. Mager, Barry F. Madore, and Wendy L. Freedman, "Metallicity-Corrected Tip of the Red Giant Branch Distance to NGC 4258," Astrophysical Journal 689 (December 20, 2008): 721-31.
- Wendy L. Freedman et al., "Final Results from the Hubble Space Telescope Key Project to Measure the Hubble Constant," Astrophysical Journal 553 (May 20, 2001): 47-72.
- A. L. Argon et al., "Toward a New Geometric Distance to the Active Galaxy NGC 4258. I. VLBI Monitoring of Water Maser Emission," Astrophysical Journal 659 (April 20, 2007): 1040-62; E. M. L. Humphreys et al., "Toward a New Geometric Distance to the Active Galaxy NGC 4258. II. Centripetal Accelerations and Investigation of Spiral Structure," Astrophysical Journal 672 (January 10, 2008): 800-16.